At sundown Thursday, families frolicked in the crashing surf at Pensacola Beach. A few surfers tried to find a wave. The beach bar troubadours played Neil Young and Eagles tunes as college kids knocked back beers. A skinny guy with a metal detector shuffled along looking for treasure.

All was as it should be, the classic chamber of commerce picture of Florida beach life.

On Friday everything was different. The families were still there, splashing around. The beach bars still sold brewskis to thirsty college kids. But in the surf line, mingled with the broken sand dollars and the calico shells, lay an army of invaders straight out of a science-fiction movie:

Thousands of shiny, reddish-brown globs, glistening in the sun — signs that the Deepwater Horizon disaster had at last stained Florida's sugar-white beaches.

Tar balls washed ashore along more than 40 miles of the Panhandle coast, from Perdido Key State Park on the western end of Escambia County to Navarre Beach in Santa Rosa County. Boats snared big tar mats floating in Pensacola Pass, and a dozen more mats were spotted late Friday in the gulf about 6 miles south of the Navarre Beach pier, according to the state Department of Environmental Protection.

Friday's oily assault marked the end of an agonizing wait for Floridians, who had been watching for six weeks as the petroleum fouled the beaches and marshes in Louisiana, then Mississippi, then Alabama. Then the winds that had kept the oil away from Florida shifted, and the misery showed up in thick glops that looked like a cross between chocolate pudding and dead jellyfish.

The first ones were spotted by Robert K. Turpin, 50, a fourth-generation Florida native who works for Escambia County as head of its marine resources department. Turpin — a tall, slender man whose cell phone ringtone is the sound of waves washing ashore — got up before dawn, put on his county uniform and drove out to Fort Pickens at 4:30 a.m.

The fort was built in 1834 to guard the pass into Pensacola Bay. Turpin said he wanted to see if what he thought of as "the enemy" — the oil spill — had somehow slipped past the fort. When he stepped out on the beach, shining in the light from a half-moon, he found his worst fears had come true.

"It was a beautiful night," he said. "I walked out on the beach and I started seeing them. Then I started seeing more and more. I took some pictures and then got on my BlackBerry and sent out an alert. They were between an inch and 6 inches big, and a quarter to half an inch thick, and they averaged about one every linear foot."

The incoming tide, which started about midnight and lasted until noon, brought more and more of the blobs, some of them as big as Frisbees.

About 8:30 a.m. Robert Reid and his wife, Chris, drove to Fort Pickens, too. They had moved to the Gulf Coast to surf and fish. Robert Reid picked up a reddish-brown blob that filled his hand, holding it up for his wife to photograph. He said it felt "ultra-gooey and smooth."

As it warmed in the sun, the oil dripped off the edge of his palm. More blobs dotted the sand nearby. "I've been looking for the oil," Reid said as his wife snapped pictures. "I just wanted to see it for myself."

When a crew showed up to check out the report of what he had found, one official who would not give his name to a reporter held out a trash bag for Reid to deposit the tar ball, then told him, "I really wish you hadn't picked that up with your bare hand."

Yet some people just couldn't resist poking the tar balls, prodding them with a bare finger — or worse. Kelsey Pawles, 17, who just graduated from high school, gathered up a dozen in her hand as if they were seashells as she strolled along the beach near the entrance to Fort Pickens. Then, when she realized they were staining her hand brown, she dumped them in a heap. She promised to wash her hand thoroughly.

County Commission Chairman Grover Robinson IV admitted that even he couldn't resist the urge to grab the glop barehanded. "It's just so hard to see it on the beach and not pick it up," he said.

And they were everywhere you looked. A five-minute walk along the beach near Fort Pickens found a dozen scattered near where least terns and Kemp's ridley turtles nested.

Katie Lawhon, a spokeswoman from the National Parks Service, said there was no need to run tests on the origin of the oil found on the Pensacola beaches. Based on the volume of tar ball reports and how widespread they were, she said there is little doubt they came from the Deepwater Horizon disaster. And it won't end anytime soon.

"Both the weather and the tides are changing," Lawhon said. "They're bringing the oil in and taking it away, and then bringing more in."

By Friday afternoon, sweaty cleanup crews in yellow boots and shiny black gloves were wending their way through the scattered beach towels and umbrellas, past the people surf fishing and swimming. They carried shovels and big plastic bags, and carefully scraped up every dime-sized tar ball they found.

State officials emphasized repeatedly that 83 percent of the 300 or so cleanup crew members were from Florida. The crew members, some of whom used duct tape to seal their pants legs to the top of their boots, said they were not allowed to speak with reporters, so verifying that number proved impossible.

Robinson, the county commissioner, said he complained to BP about how the cleanup crews took nearly eight hours to take action after Turpin's early morning alert. He pointed out that county crews clean the beach 365 days a year, yet BP officials did not consult the county about how best to do the job.

"We know to do it early in the morning, before the crowds show up, and we don't have our people out ogling at women on the beach," Robinson told reporters.

The cleanup crews were not the only anomaly at the beach. By the curb at Pensacola Beach's pavilion were a dozen television trucks, lined up like an Old West wagon train. Reporters tracked beachgoers across the sand.

When Lucia Bustamante, BP's community outreach coordinator, agreed to speak with one camera crew, she was quickly surrounded by microphones.

The big question was what would happen today. Would the blobs continue assaulting Florida's beaches? Would it be something thicker and messier staining the sands? Bustamante said she couldn't say.

"What's going to hit and when," she said, "would be mere speculation on my part. . . . I wouldn't like to speculate."

Meanwhile Robinson tried to put the best face on a bad situation. He pointed out that thousands of people still showed up Thursday to enjoy the sun and sand.

"There are plenty of things for you to do in Pensacola Beach," he said. "If you went to the beach and walked on the sand and not on the shoreline, then you were not in any danger."